First connect the AP to the same network as the existing AP, make sure they form a cluster. Then you can disconnect the AP from the wired and use external power somewhere in the wireless reach of the existing AP and the AP should mesh automatically.
Advice would be to not mesh, unless absolutely nescessary. You will sacrifice most of the 5GHz bandwidth for the mesh link and the APs are required to share the same 5GHz channel which is not good for performance either.
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Herman Robers
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If you have urgent issues, always contact your Aruba partner, distributor, or Aruba TAC Support. Check
https://www.arubanetworks.com/support-services/contact-support/ for how to contact Aruba TAC. Any opinions expressed here are solely my own and not necessarily that of Hewlett Packard Enterprise or Aruba Networks.
In case your problem is solved, please invest the time to post a follow-up with the information on how you solved it. Others can benefit from that.
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